Power distribution systems that have a limited peak power capability or a high source impedance, such as site supply generators, are often susceptible to abnormal operation in response to the current drawn at power up from the loads connected to the power distribution system. The present invention provides a load control module for a lighting control system operable to start up a plurality of the lighting loads in sequence to reduce stress on the power distribution system. The lighting loads are each turned on as part of a startup sequence at predetermined times after an output voltage of the power distribution system has stabilized. The lighting control module is operable to wait for a predetermined amount of time for the startup sequence to begin before turning on the lighting loads.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of controlling a load control device operable to control the amount of power delivered to an electrical load from a power distribution system, the method comprising the steps of: applying power to the load control device; and waiting for a first control signal for a first predetermined amount of time after the step of applying power before turning on the electrical load, the first control signal representative of stable operation of the power distribution system; maintaining the electrical load off if the first control signal is received within the first predetermined amount of time after the step of applying power; turning on the electrical load after a second predetermined amount of time from when the first control signal is received; and turning on the electrical load if the first control signal is not received within the first predetermined amount of time after the step of applying power.
2. The method of claim 1 , further comprising the steps of: storing the second predetermined amount of time in a memory prior to the step of turning on the electrical load after a second predetermined amount of time after the step of receiving the first control signal.
3. The method of claim 1 , wherein the step of turning on the electrical load after a second predetermined amount of time after receiving the first control signal further comprises the steps of: receiving a second control signal via a communication link; and turning on the electrical load in response to the second control signal.
4. The method of claim 1 , wherein the electrical load comprises a lighting load.
5. The method of claim 1 , further comprising the step of: determining if a startup-delay mode is enabled prior to the step of waiting for a first control signal.
6. The method of claim 5 , wherein the step of determining if a startup-delay mode is enabled comprises determining if a startup-delay bit is set in memory.
7. The method of claim 6 , further comprising the steps of: receiving a startup delay configuration signal; and setting the startup-delay bit in a memory in response to the step of receiving a startup-delay configuration signal.
8. A load control module for controlling the amount of power delivered from a power distribution system to an electrical load, the load control module comprising: a load control circuit adapted to be coupled in series electrical connection between the power distribution system and the electrical load; a controller coupled to the load control circuit for controlling the amount of power delivered to the electrical load; and a communication circuit coupled to the controller, such that the controller is operable to control the load control circuit in response to a first control signal received by the communication circuit, the first control signal representative of stable operation of the power distribution system; wherein the controller is operable to wait for the communication circuit to receive the first control signal for a predetermined amount of time after powering up, the controller operable to maintain the electrical load off if the first control signal is received within the first predetermined amount of time after powering up and to turn on the electrical load after a second predetermined amount of time from when the first control signal is received, the controller further operable to turn on the electrical load if the first control signal is not received within the first predetermined amount of time after powering up.
9. The load control module of claim 8 , further comprising: a memory coupled to the controller for storage of the second predetermined amount of time.
10. The load control module of claim 8 , wherein the controller is operable to turn on the electrical load after the second predetermined amount of time from when the first control signal is received by receiving a second control signal and controlling the load control circuit to turn on the electrical load in response to receiving the second control signal.
11. The load control module of claim 8 , wherein the electrical load comprises a lighting load.
12. The load control module of claim 8 , wherein the controller is operable to determine if a startup-delay mode is enabled prior waiting for the communication circuit to receive the first control signal for a predetermined amount of time after powering up.
13. The load control module of claim 12 , further comprising: a memory coupled to the controller for storage of a startup-delay bit, the controller operable to determine that the startup-delay mode is enabled if the startup-delay bit is set.
14. The load control module of claim 13 , wherein the controller is operable to set the startup-delay bit in the memory in response to receiving a startup delay configuration signal.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
September 13, 2007
August 24, 2010
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